Dead-reckoning tracer



DEAD RECKONING TRACER Filed March 17, 1925 avwauto'a Patented Dec. 16, 1930 ruuiraoflsrArss PATENT OFFICE xonrmnn r. was, or naooxmm, new Yoax, nssronoa, BY masnn ASSIGNMENTS,

ro srnaar ernosoorn couramr, me, or BROOKLYN, NEW 10281, a conrona- TION on NEW Yonx :nnan-nnoxonme 'rnacnn Application and March 17, 1925. Serial No. 16,140.

This invention l relates to dead reckoning tracers which are designed to produce a v1s1- ble indication or record ,upon a map or'chart of the course and" position of a craft. Whilemy invention is capable of use for the afore- I erator to attain any objective within the confines. of his map or chart and to know his exact position at all times, and willprove of the eatest value in such vehicles as tanks, whic are totally enclosed so that the operator" or operators therein cannot get their bearings outside of the craft.

It is a further object of this invention to provide, means for making a record on a chart which shall show the actual course of the craft over rough terrain within the scope of and to the scale of the chart being used. For this purpose it is necessary to provide means for eliminating from the record'the vertical component of travel when the vehicle is moving uphill or downhill, since it is only the horizontal component of 'such travel that measures the actual distance traveled. It is further necessary in order to ac- 30 complish this purpose, where the record of travel is made upon a movable chart,

to r0- vide some means for traversing the recording pen porportionally to any lateral component r of movement of the vehicle out of parallel with the lengthwise movement of the chart.

In this case, the deviation or change in head ing is indicated by a line at an angle to the,

heading, I provide means for automatically slowing up "and reversing the movement ofthe chart in pro ortion to the angular change inheadingl'of the vehicle and conversely increasing t same or opposite direction as the course of e movement of the chart in the the vehicle again approaches parallelism w th the longitudinal axis of the chart. In this manner complicated maneuvers may be executed by the vehicle within the limits of the chart and will be accurately traced to scale on the chart. l

Further objects of this invention will become apparent in the following detailed de scription thereof.

In the accompanying drawings Fig. 1 isa plan view of a dead reckoning tracer embed ing my invention. Fi 2 is a ront elevation of certain variable riving mechanism in the indicator of Fig. 1.

eferring to the drawings I have shown my dead reckoning tracer as applied to avehicle by means of a frame or platen 10 movable integrally with said vehicle and upon which the indicator is mounted. Said tracer comprises a moving chart 11, which may be of the roll type, adapted to be wound or unwound from one roll 12 to the other 13. Said chart may be driven to unwind the same from roll 12 and wind it upon roll 13 by some suitable driving mechanism, which, in the present instance, may comprise a chain 15 driven from an axle of the vehicle proper to drive a shaft 16, and thence b way of variable friction gearing 17-18,tliepu se ofwhich will be hereinafter more fu 1y described, and gearing 19-20 -2122-23 24 and variable friction gearing 25-46, the pur ose of which will be also more fully descri ed hereinafter, to rotate shaft 27, and thence through suitable gearing, only one element 28 of which is shown, to drive sprocket wheels, not. shown, adapted to engage per? forations 29 in the chart 11 to feed the same. Clock springs 52, 53 are provided on each roller by WhlCh tension is maintained on the chart. A square shank at 54 is provided for a key by which the springs can be ound U on saidchart is adapted to operate a mar er or stylus 30 carried upon a bar 31 operating in suitable bearin s 32 and having a rack 33 formed at one on thereof, engaging with a pinion 34 whereby, upon rotation of the pinion in one direction or the other,

- headin the stylus 30 ma be operated transversely of the chart 11. he pinion 34 may be actuated through a train of caring, such as 35-3637, and the varia 1e friction ear drive 38-39, the purpose of which wi be more fully described hereinafter, to be oper-- ated from a direction indicator, which may be a repeater compass 40 controlled by a .master gyroscopic compass 41 or other azimuth indicator such as shown, for exampIle, in the patent to Elmer A. Sperry, 0. 1,255,480,"granted February 5,1918. The reeater com ass 40 may be positioned on i rame 10 i desired, and the master compass 41 may be located any placewithin the vehicle, the said re eater compass 40 being controlled from a istance in the ordinary and well known manner.

In order that com ass 40 may control the stylus 30 to operate t e same when change in occurs, there is mounted upon the same s aft 42 that carries the card 40 a cam 43 which engages a shaft 44 slidable in a suitable bearing 45 and carrying the friction roller 39 at its other end. A spring 46 maintains the shaft 44 in engagement with said cam. The parts are so 1positioned that when the vehicle is on any eading corresponding to the horizontal axis of a particular strip of chart or map, shaft 44 engages that portion of the cam which will cause friction disc 39 to stand in the center of'friction disc 38 so that there is no movement of said friction disc 38 and hence no movement of the gear train 35-36-37 or of the stylus 30 in a direction transverse to the chart. So that if the course to be maintained is represented by a line drawn centrally, lon itudinally of the chart 11 and the stylus is initially laced uplon said line or any line parallel t ereto w en thevehicle is trained upon said course, then the continued movement of the vehicle on the prescribed course will cause stylus 30 to mark a line coincident with, or parallel to, the longitudinal axis of the chart 11. If, however, the vehicle deviates from" the initial heading, then shaft 44 will engage other portions of the cam 43 to cause friction disc 39 to rotate in one direction or the other according to the direction of deviation and thus move stylus 30 transversely of chart 11 in one direction or the other to trace a line at an angle to the central longitudinal line.

It will be understood that as the chart 11' moves in proportion to the ground speed of the vehicle and the scale of the chart, then the central line the relation of a hypothenuse of a ri ht-angled trian -le to its side. In order that lines indicating deviation from course shall also represent true linear distances according to tne same scale as before, I provide means for slowing up thechart relative to the ground speed when such deviation occurs and in proportion to the degree of said deviation. For this purpose I mount upon the same shaft 42 that carries cam 43 a similar cam 50 positioned with respect to said cam 43 so as to be opposite in phase thereto. Thus, when shaft 44 is in engagement with the portion of the cam 43 which causes friction disc 39 to be ositioned centrally of friction disc 38, shat t '51 is in such position relative to cam 50 as to cause friction disc 25 to be ositioned at the extreme outer edge of riction disc 26. Inter reting this another way, when the vehic e is travelling on a course where stylus 30 is stationary, a line traced on the chart by the movement of the chart will correspond to scale with the actual distance covered by the vehicle. This will also be true when the vehicle changes its heading because friction disc 39 moves outwardly on friction disc 38, and friction disc 25 moves inwardly on friction disc 26 to slow u the chart in accordance with the explanatlon hereinbefore given. The lines indicating changes of heading can thus be measured according to the same scale as lines parallel to axis of chart to 've a true indication'of distance traveled, an the path followed by the vehicle is accurately traced on the map.

In the case of a vehicle whichmay travel upon courses other than truly horizontal, it will be apparent that the vertical component of movement will ordinarily introduce an error in the record or position indicated on the map. In order that the said record may indicate accurately on the map, I provide a second means for controlling the speed ratio of the chart with respect to the ground spec'-. of the vehicle when the vehicle travels on any but a horizontal course and for controlling it in proportion to the degree of inclination of said vehicle. For this purpose I may provide agyroscope 60, including a rotor having a vertical spinning axis 61 journaled in a casing which is itself ournaled upon horizontal bearings 62 in a gimbal ring 63 supported on horizontal bearin s 64 at right angles to bearings 62. This is a vertical gyro for maintaining a horizontal base-line and is so ositioned that any inclination of the ve icle will cause relative movement about axis 64. Such movement will cause relative movement between trolley 65 movin with the vehicle and contacts 66 maintaine in a horizontal plane by the said vertical gyro, so that said trolley 65 movesinto engagement with one or the other of said contacts to close the circuit through a motor 67 which operatesa loo a cam slot 72 in which 0 crates one end of a. member 7 3, the other en of which is slidable upon shaft 16 and carries therewith the friction disc 17 The parts are so positioned that when, the vehicle is traveling horizontally and trolley65 is on the insulated strip'between the two contacts 66, thenmember 7 3 is at the outer end of cam'slot 72 to maintain friction disc 17 at theouter edgeof friction disc 18 to drive the chart, at its greatest speed relative to the ground speed of the vehicle.

When, however, thevehiclebecomes inclined and contact 65 engages one ortheother. of

contacts 66,:then caniroller 71 is operated to move member 7 3 and friction disc 17 toward the center of friction disc 18 to slow up the speed ofthe chart relative to the groundspeed -ofthe vehicle. Motor 67 operates follow-up gears 69 and 77 to return trolley 65 to neutral position. It will be understood that V l the greater the inclination the longer the time during which motor 670 erates, andthe further toward the center 0 disc 18 will disc 17 be operated, or in other words, the greater the inclination the slower the speed of chart 11 compared with the ground speed of the vehicle.-

For synchronizing a given strip of'chart or map, there may be rotatably mounted on frame 10 a ring 80 having frictional engagement therewith, so that it may be moved relative to the frame by handle 80'. Ring 80 carries 'the lubber .line 81 shown in its zero position, which, in conjunction with the card 40, can be synchronized with themaster compass. The process of set-ting for a given chart or. map whose heading is known by 1138, longitudinal or lengthwise axis is as follows: The vehicle is turned until the required headingis indicated on the master compass. This turning of the vehicle with respect tocard 40, however, will have moved shaft 44 out of engagement with the portion of cam 43 which it should engage when the vehicle is on the required heading so thatfriction disc 39 may occu p thecenter of frictiondisc 38. To

reme y this condition a hand synchronizing mechanism is provided. Therefore, to synchronize the chart with the cams 43 and 50, after the vehiclehas been given the proper heading, set lubber line 81 onzero and by handcrank 83 move the repeater card until its north point coincides with the lubber line then shift lubber line until the repeater card sider to represent the best embodiment there- .of, but I desire to have it understood that the apparatus shown-is only illustrative and that t e invention can be carried out by other means. Also, whilev it is designed to use the various featuresfandelements in the combination and relations described, some of these .may be altered and others omitted without interfering with the more general results-outlined, and the invention extends to such use.

Having described my invention, what I claim and desire to secure by Letters Patcut is:

1. In combination with a vehicle, a dead reckoning tracer comprising recording mechanism including a movable chart and a marker, means whereby said marker is moved in accordance with deviations from a predeterminedcourse inazimuth of said vehicle,

means for moving said chart, andmeans whereby said last named means is effective only as lon as said vehicle has a componentof travel a ong said course. i

2. In combination with a vehicle, a dead reckoning tracer comprising recording mechanism including a movable chart and a marker, means whereby said marker is moved in accordance with deviations from a predetermined course in azimuth of said vehicle, and means for moving said, chart continuously as long as said vehicle has a component of travel along said course and for reversing the movement of said chart when said vehicle has a component of travel in a direction opposite to said course. i

3. In combination with a-vehicle, a dead reckoning tracer comprising recording mechanism including a movable chart and a markor, means whereby said marker is moved in accordance with deviations from a predetermined course in azimuth of said vehicle, means for moving said chart, and means for controlling the rate of movement of said chart in accordance with the degree ofdevlatlon of said vehicle from said course.

4L. In combination with a vehicle, a dead reckoning tracer comprising recording mech- I anism including a movable chart and a mark er, means whereby said marker is moved in accordance with deviations from a predetermined course in azimuth of said vehicle, means for moving said chart, and means for decreasing the rate of movement of said chart as the degree of deviation of said vehicle fromjsaid course increases.

5. In combination with a vehicle, a dead reckoning tracer comprising recording mechanism including a movable chart and a marker, means whereby said marker is moved at a rate proportional to the degree of deviation of said vehicle froma predetermined course, and means for moving said chart at a rate inversely proportional to the rate of movement of said marker.

6. In combination with a vehicle, a dead reckoning tracer comprising recording mechanism including a movable chart and a marker, means whereb said marker is moved in accordance with eviations from a predetermined course in azimuth of said vehicle, means for moving said chart continuously as long as said vehicle has a component of travel along said course. and for-reversing marker,-means whereby'said marker is actuated in accordance with the course of said vehicle, means for moving said chart, and

means for controlling the rate of movement of said chart in accordance with the course of said vehicle in azimuth and in elevation.

8. In combination with a vehicle, a deadreckoning tracer comprising recording mechanism including a movable chart and a marker, means including a repeater compass for actuating said markerin accordance with the course of said vehicle, said repeater compass having a shiftable lubber line, means whereb the position of said compass relative to sairl chart may be predetermined and meansfor adjusting said lubber line so that the repeater compass may always bear predetermined relation to the chart and at the same time indicate the actual heading in azimuth of the vehicle. p

9. In. a vehicle having a master compass, a dead-reckoning tracer comprising recording mechanism including a movable chart and a marker, means whereby said marker is actuated in accordance with the course of said vehicle means for moving said chart,

and means or controlling the rate of move ment of said chart in accordance with the same time indicate the actual heading in azimuth'of the vehicle regardless of said adj ustment relative to the chart.

10. In combination with a vehicle, a deadreckoning tracer comprising recording mech-- anism including a movable chart and a marker, means whereby said marker is actu ated in accordance with the course of said vehicle, means for moving said chart, and means for controlling the rate of movement of said chart in accordance with the course 'means of said vehicle in elevation, said last named means including a universally mounted gyroscope.

11. 'Incombination with a vehicle, a deadreckoning tracer comprising recording mechanism including a movable chart and a marker, means whereby said markeris actuated in accordance with the course of said vehicle, means for moving said chart including 'a variable gearing, and means for controlling the rate of movement of said chart in accordance with the course of said vehicle in azimuth, said last named means including a compass, a cam controlled thereby, and means whereby said cam controlssaid variable gear.

12. In combination with a vehicle, a deadreckoning'tracer comprising recording mechanism including a movable chart and a marker,'means whereby said marker is actuated in accordance withthe course of said vehicle, means for moving said chart including' a variable gearing, and means for controlling the rate of movement of said chart in accordance-with the travel of said vehicle in elevation, said last named means including a universally mounted gyroscope, a cam controlled thereby, and means whereby said cam controls said gearing.

13. In combination with a vehicle, a deadreckoning tracer comprisin recording mechanism including a mova le chart and a marker, means whereby said marker is actuated in accordance with the course of said vehicle, means for moving said chart including a lurality of variable gearings, and means or controlling the rate of movement of said chart in accordance with the travel of said vehicle in azimuth and in elevation. said last named means including a compass,- means for maintaining a horizontal base line, a cam controlled by said compass, a second cam controlled by said last' named means, and means whereby said cams control said gearings.

'14. In combination with a vehicle, a deadreckoning tracer comprisin recording mechanism including a movafile chart and a 'marker, means whereby said marker is actuated in accordance with the course of said vehicle, means for moving said chart including'a plurality of variable gearings, and or controlling the rate of movement of said chart in accordance with the travel. of said vehicle in azimuth and in elevation, said last named means including a compass, a universally mounted gyroscope,- a cam controlled by said compass, a second cam controlled by said gyroscope, and means whereby said cams control said gearings.

In testimony whereof I have aflixed my signature.

MORTIMER F. BATES. 

